(Insect compound eye) pseudo-pupil of the formation mechanism and the related measurement techniques
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Description
When we looked at a relatively large compound eyes of insects (such as praying mantis, locusts, etc.) of the eyes, the eyes will find that it actually has a black pupil! And whatever we (the observer) how to move, that the pupil-like black spots are always facing us, so we inevitably wonder: how an insect compound eye and the human eye when the same become it? This is not really the pupil, it is called pseudo-entomology on the pupil (pseudopupil). The reason why there will be pseudo-pupil, there is a very complex optical reasons.
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Important relevant research data 1 (the information very rare!)
The following information comes from the English original from an online pdf: Special thanks to this sharing of information with the cocoon of my comrades Park! ! Source Address: http://web.neurobio.arizona.edu/gronenberg/nrsc581/eyedesign/visualacuity.pdf The study file Description: (This is a British research scientist in 1997) annu. rev. entomol. 1997. 42:147 ╟ 77 copyright c 1997 by annual reviews inc. all rights reserved visual acuity in insects michael f. land sussex centre for neuroscience, school of biological sciences, university of sussex, brighton bn1 9qg, united kingdom key words: vision, eye, optics, acute zone, interommatidial angle abstract the acuity of compound eyes is determined by interommatidial angles, optical quality, and rhabdom dimensions. it is also affected by light levels and speed of movement. in insects, interommatidial angles vary from tens of degrees in apterygota, to as little as 0:24 in dragonflies. resolution better than this is not attainable in compound eyes of realistic size. the smaller the interommatidial angle the greater the distance at which objects-prey, predators, or foliage- can be resolved. insects with different lifestyles have contrasting patterns of interommatidial angle distribution, related to forward flight, capture on the wing, and predation on horizontal surfaces.
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The causes of pseudo-pupil
伪瞳孔成因
Just under what I was looking for (this explanation I'm really looking forward to a very long time ah!) more recently, measurements of "Delta phi" have involved the use of the pseudopupil in its various forms. the pseudopupil, typically a black dot that appears to move around the insect's eye as the observer's viewpoint changes, marks the ommatidia that image-and absorb light from-the observer. thus a line joining the pseudopupil to the observer's eye is the direction of view of the ommatidia in that region. local measurements of "Delta phi" can be made easily by rotating the eye through a known small angle (a) and counting the number of ommatidia (b) crossed by the pseudopupil, "Delta phi" is then a = b. typically, measurements are made with the animal centered on a goniometric stage, and the pseudopupil is observed or photographed through a microscope (23). where the interommatidial angles are small, as for example in the acute zones of dragonfly eyes, the best pseudopupil image lies some distance below the cornea (the deep pseudopupil), and it is important to use a small microscope aperture so that both cornea and pseudopupil can be visualized together. because the pseudopupil is actually a magnified image of both the rhabdom and its surrounding pigment, its center must be located to find the ommatidial axis direction. usually this is not a problem, but where interommatidial angles change rapidly, the pseudopupil becomes asymmetric and care is required. That is, we see the eyes of mantis and other insects have always looked at his pupil (the black spots called pseudopupil, namely, "pseudo-pupil"), simply because our vision of being re-absorbed by the eyes of our rod cells, as shaft of light which was black. So I see some people's interpretation of that "black spots are on the horizon at the fundus reflex and was out of their own (the observer) look like" interpretation is not accurate. * The researchers also mentioned here can be widely used to measure a small eye (ommatidium) number of methods, called "delta-phi", I understand means "angle variation," as long as with a small aperture microscope at the targeting of a compound eye (according to my knowledge of photography, small aperture means that the large depth of field), so that determination can ensure that both the cornea and the pseudo-pupil is seen (we have seen in the cornea under the pseudo-pupil ), because in fact the rod bundle and its surrounding pigments magnify the image, so we use the microscope to locate the pupil is actually a rod cell (according to my understanding of entomological knowledge, this "pseudo-pupil localization method" should is more accurate because of the small eyes (inter-ommatidium) angle is very subtle, pseudo-pupil is found naturally on the location to determine a small eye of the. use of such instruments one by one on the compound eyes to the number of small eyes, a certain country can be better than our biological Orsay training area in the count and then talk about ways to divide the soil is much more scientific!) ... but they stressed that road, if the angle of the small eyes the dramatic changes in pseudo-pupil becomes "asymmetric" (I understand that "bad elusive" means). Thus, as the representative for the mantis insect eyes doubts, I believe the above interpretation of British scientists. Their measurements and theoretical statements are very strict.
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Under different conditions the pseudo-pupil
After the report continues: in dark colored eyes the pseudopupil is often not apparent. crossed polarizing fibers can be used to cut down reflections, but a more generally useful technique is known as the antidromic pseudopupil (15). here the center of the head is illuminated from below, and light finding its way into the proximal part of the rhabdom (ere) s is emitted from their distal tips. this produces a luminous pseudopupil, which can be examined in the sameway as the dark "orthodromic" kind. pseudopupil methods are discussed and reviewed in references (14, 23, 76, 87). This means that (if this is wrong please point out my reasons), and insects are also pseudo-pupil in the dark, but because of its eye on the construction of a "staggered polarization fibers," blocking the reflected light (which I did from had not noticed, for me is really a new discovery.) article pointed out, the bottom of the first insect light irradiation, the rods can be in a similar beams (small eyes) at the end (that is, the deepest on the cutting edge anatomy) see the light, this state, "the pseudo-pupil light" is called "reverse-type pseudo-pupil (antidromic pseudopupil)", and that usually can not light the pseudo-pupil (the cis-called pseudo-pupil, English orthodromic pseudopupil) the same measurement method (my translation of the above mentioned) to be determined. (The above is just the original study a small part, further translation work remains to be added.)
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In short, the insect's compound eye compound eye is
Our observers have seen the "pupil" is a positive eye on the position of the small effect caused by light absorption.
